fix: add Minecraft 26.x scrolls

[druid-infra]

Summary

• add Minecraft 26.x scrolls to the existing update PR
• extend the Minecraft catalog beyond 1.21.11 using live upstream version data
• keep the existing branch/PR and append the new family/version coverage

Versions added

• Vanilla: 26.1, 26.1.1, 26.1.2, 26.2
• PaperMC: 26.1.1, 26.1.2, 26.2
• Spigot: 26.1, 26.1.1, 26.1.2, 26.2
• Forge: 26.1, 26.1.1, 26.1.2, 26.2

Included repo changes

• add new versioned scroll directories for the versions above
• update .build/vars.json and .build/artifacts.json for Vanilla, PaperMC, Spigot, and Forge
• update .github/workflows/fetch-papermc.yml
• update .github/workflows/fetch-mc-forge.yml
• update .github/workflows/fetch-spigot.yml
• update scripts/push.sh
• move these new 26.x scrolls to Java 25 runtime images and set jdkVersion: 25 in build metadata

Validation

• git diff --check
• JSON parse across scrolls/minecraft/**/*.json
• YAML parse across scrolls/minecraft/**/*.yaml and .github/workflows/*.yml
• bash -n scripts/push.sh
• bash -n scrolls/minecraft/forge/fetch.sh
• ./scripts/validate_all_scrolls.sh could not run here because go is not installed in this environment

[druid-infra]

Error: This repo is not allowlisted for Atlantis.